Years ago an artist going by the name SC0RP released music to be used for both Nexuiz and Xonotic (including an epic track that was almost used for the menu). Some of his music found it's way into both games, however two of his latest tracks have yet to be used and the links to them and their sources have since rotted. I dug through some old DVDs and found those tracks and sources for the second versions of said tracks (he released the source after revising) and have uploaded them onto my dropbox.